Comparison of Stress and Learning Effects of Three Different ...

HOBFOLL (1989) offered a new theory called the ‘’conservation of resources’’ (COR)
theory which is also based on the ‘’psychological stress’’. He furthermore states that the loss
of resources is the primary source of stress. According to the COR theory, stress occurs in
cases of loss or threat of resources, or of a lack of gain following the investment (HOBFOLL
1989, HOBFOLL et al. 1996).
McEWEN and WINGFIELD (2003), however, discussed the stress concept within the
framework of allostasis and defined stress as “events that are threatening to an individual and
which elicit physiological and behavioral responses as a part of allostasis in addition to that
imposed by normal life cycle”. In this manner, they introduced two new concepts: allostatic
load, i.e., adaptive responses to daily and seasonal individual demands such as migrating,
breeding, molting etc. and allostatic overload, i.e., the state in which the energy requirements
exceed the energy income of the individual, or the condition in which the organism continues
to store energy though energy requirements are not exceeded, such as stress related food
consumption.
URSIN and ERIKSEN (2004) recently developed a stress theory called the ‘’Cognitive
Activation Theory of Stress’’ (CATS) based on neurophysiological activation and arousal
concepts. According to CATS, the stress response is ‘’an alarm which produces general and
unspecific neurophysiological activation whenever homeostatic imbalance or threat to
homeostasis and life of the organism occurs’’.
ERIKSEN et al. (1999) emphasized that the stress response is dynamic and develops in phases
and, also, that the time course of stress response is very important for evaluating relationships
between the stressors and the observed physiological responses, as well as for any
pathophysiological consequences of such relationships. CATS assumed that ‘’the initial stage
of the response-characterized by positive feedback and feed-forward mechanism- is followed
by the activation of the homeostatic mechanism, and subjects with efficient coping show the
fast- and short-lasting catecholamine response, while subjects with high defense mechanisms
(related to stimulus expectancies) may show more signs of prolonged activation‘’. URSIN and
ERIKSEN (2004) proposed that when the expectancies, which are attached to the responses,
are positive, there is no health risk in a healthy organism, and that the ill-effect only occurs in
case the lack of coping.
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